[sergio]

Hello this is my first post on this forum.
I want to create trains and some routes for OR.
I hear somewhere that OR can handle more polys than MSTS.
Generally speaking, what is the poly limit and texture for Locomotives, wagons, etc., in comparation to MSTS.

[captain_bazza]

Yes, OR can handle higher poly models, over 100,000 poly faces at least, but it also depends on how the sub-objects are setup. Not certainly about the upper limit number of textures per model. You can use 2048x2048 32bit, which gives nice resolution and can be handled by level entry graphics cards. You will only learn by experimenting.

The absolute maximum of polys and textures is open to discussion. If you browse these forums you will get an idea of the models that are possible. If you intend modeling, the time you have left for route building will be less. Both modeling and route building are very time consuming in their own right.

Welcome to ET.

Cheers Bazza.

[disc]

sergio, on 20 November 2015 - 03:14 AM, said:

Hello this is my first post on this forum.
I want to create trains and some routes for OR.
I hear somewhere that OR can handle pore polys than MSTS.
Generally speaking, what is the poly limit and texture for Locomotives, wagons, etc., in comparation to MSTS.

no limits, but that doesn't mean that you should use unnecessary polycounts and textures, as it's still makes the game run slower.

[RTP]

I am currently using-developing models with >100000 polys without a problem.

The poly load comes mainly from the route, trees and so.

Regards.

[captain_bazza]

In the end, as always, is the power of the computer, including the video card. This has an effect once the scene gets a bit cluttered with objects, static and dynamic.


CB.

[sergio]

thanks for your reply.
wow, 100000 is a big margin for me, probably i will not go far away.

[Genma Saotome]

Open Rails can do a lot more work in the same amount of time as could MSTS but that doesn't mean it is ok to be careless with your models, especially WRT named parts and the number of textures.

There is a simple proxy for the amount of work OR is doing at any one moment -- in the f5 key sequence, on the last display look for "Primitives". The first number is the sum of how many Draw Calls are occuring per frame. A Draw Call is the action of passing data from the CPU to the graphics driver (and on to the GPU). Next, look at the Render Process Percentage. That number tell you how much of the CPU's available time per frame the work to perform those draw calls is taking. If the CPU percentage is 100% it's telling you that any additional Draw Calls will result in a lower frame rate.

For someone who makes models then you do need to understand what in your work is translated into draw calls -- the answer is (mostly) the number of textures. Count the textures and you have the minimum draw call count. However there are some features of models that will cause a texture to generate more Draw Calls: Any polys that are transparent, or have any form of shine or illumination and any polys that are part of a named part will all produce more Draw Calls.

It works like this: Say you have textures A, B, and C and all are used in various places. In addition, one portion of C has transparency. This produces four Draw Calls -- one for each texture file and another for the transparency.

Second example... same as above plus we add two named parts, using all three textures and transparency. Three for the files, a fourth for the transparency (as per the first example) four more for each of the named parts -- a total of twelve Draw Calls for the three textures. IOW, named parts can be very costly! The ideal soluition here (assuming the named parts are required) is to see if you can rework the content of the texture files so whatever is applied to the polys in the named parts are all one one texture and nothing on that texture is being used elsewhere. That would change the Draw Call count from twelve to eight.

Bottom line is the optimum model uses no more named parts than are required by the sim (e.g. Bogie1) and the least number of material types and texture files as are really necessary for the model.

[disc]

Also fewer bigger textures are better than more smaller textures. I'm sure that OR can handle 4096x4096 textures too.

Genma Saotome, on 20 November 2015 - 01:10 PM, said:

Any polys that are transparent, or have any form of shine or illumination and any polys that are part of a named part will all produce more Draw Calls.

Are you sure that such simple shaders generate more than one draw calls? There are multi pass materials of course, like weather effect glass, normal mapped surfaces, but OR have just simple, probably single pass materials.

BTW <100000 triangle should be enough for any locomotive. An optimized loco with 4 very detailed pantographs, and a lot of cylindrical insulators, and cables on the top, with very detailed bogies, and body can fit in 70k triangles.

[Genma Saotome]

disc, on 20 November 2015 - 01:37 PM, said:

Are you sure that such simple shaders generate more than one draw calls? There are multi pass materials of course, like weather effect glass, normal mapped surfaces, but OR have just simple, probably single pass materials.

Pretty sure... open up your model in ShapeViewer, go to the Hierarchy window and count to brown boxes. Those are your Draw Calls. Add some material types and the boxes increase, add named parts and they increase even more.

[James Ross]

disc, on 20 November 2015 - 01:37 PM, said:

Are you sure that such simple shaders generate more than one draw calls? There are multi pass materials of course, like weather effect glass, normal mapped surfaces, but OR have just simple, probably single pass materials.

Yes, we have two-pass alpha blending. I'm not especially happy about it (due to the overhead) but it's there.